Polysilicon plug bipolar transistor for phase change memory

Abstract

Memory devices and methods for manufacturing are described herein. A memory device described herein includes a plurality of memory cells. Memory cells in the plurality of memory cells comprise respective bipolar junction transistors and memory elements. The bipolar junction transistors are arranged in a common collector configuration and include an emitter comprising doped polysilicon having a first conductivity type, the emitter contacting a corresponding word line in a plurality of word lines to define a pn junction. The bipolar junction transistors include a portion of the corresponding word line underlying the emitter acting as a base, and a collector comprising a portion of the single-crystalline substrate underlying the base.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is related to co-pending U.S. patent application Ser. No. ______ entitled “Polysilicon Plug Bipolar Transistor with Self-Aligned Memory Element”, filed on ______ (Attorney Docket No. MXIC 1859-1).PARTIES TO A JOINT RESEARCH AGREEMENT[0002]International Business Machines Corporation, a New York corporation, and Macronix International Corporation, Ltd., a Taiwan corporation, are parties to a Joint Research Agreement.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]The present invention relates to high density memory devices based on phase change based memory materials, including chalcogenide based materials and on other programmable resistive materials, and methods for manufacturing such devices.[0005]2. Description of Related Art[0006]Phase change based memory materials, like chalcogenide based materials and similar materials, can be caused to change phase between an amorphous state and a crystalline state b...

AI Technical Summary

Benefits of technology

This patent describes a memory device that includes a single-crystalline semiconductor substrate with multiple word lines and memory cells. The memory cells are made up of bipolar junction transistors and memory elements. The device also includes dielectric trenches and doped polysilicon plugs for electrical coupling. The technical effects of this invention include compatibility with CMOS peripheral circuitry, simplified design integration, and improved manufacturing processes. Additionally, the invention addresses the complexity of design integration and manufacturing processes associated with phase change memory cells.

Problems solved by technology

Issues have arisen in obtaining the necessary current for phase change memory cells having field effect transistor access devices due to the relatively low current drive of field effect transistors.

Bipolar junction transistors can provide larger current drive than field effect transistors, but the integration of bipolar junction transistors with CMOS peripheral circuitry is difficult and results in highly complex designs and manufacturing processes.

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